welding bottle size

[wheelchairman]

OK just bought my hobby welder and now i need a bottle to run gas. I can buy a

20cf for 68
40cf for 95
80cf for 145


I know most of you will say the largest i can afford but I dont wanna be pushin around a cart with a huge bottle and a tiny welder.

I will go by airgas in a couple days to get prices there but these came off this ebay store  http://stores.ebay.com/Welding-Supplies-from-IOC_Gas-Cylinders-TANKS-BOTTLES_W0QQcolZ4QQdirZ1QQfsubZ11QQftidZ2QQtZkm

[Tolly]

I would go for the 145. it is the best bargain, and running out of gas sucks.